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Haris Iqbal" , Jack Wang , Jason Gunthorpe , Leon Romanovsky Cc: Shuangpeng Bai , linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [BUG] RDMA/rtrs-clt: race between close_work submission and synchronous close Date: Sun, 20 Sep 2026 23:33:36 -0400 Message-ID: <20260921033339.1320291-1-shuangpeng.kernel@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-rdma@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Hi Kernel Maintainers, I hit the following report while testing current upstream kernel: KASAN: slab-use-after-free in rtrs_clt_stop_and_destroy_conns on commit: 93f51579e7df248780214094418f205253383cc5 (2026-09-20) To help trigger the bug more reliably, we applied a minimal diagnostic patch that only adds delays and print statements. The reproducer and .config files are here. https://gist.github.com/shuangpengbai/1b0782d283051b34df6548d387be90a6 I'm happy to test debug patches or provide additional information. Reported-by: Shuangpeng Bai [ 86.996512] ================================================================== [ 86.996866] BUG: KASAN: slab-use-after-free in rtrs_clt_stop_and_destroy_conns (./include/linux/instrumented.h:82 ./include/linux/atomic/atomic-instrumented.h:32 drivers/infiniband/ulp/rtrs/rtrs-clt.c:2237) [ 86.996866] Read of size 4 at addr ffff8881038672fc by task kworker/0:0/9 [ 86.996866] [ 86.999871] Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 86.999871] Workqueue: rtrs_client_wq rtrs_clt_close_work [ 86.999871] Call Trace: [ 87.001599] [ 87.001599] dump_stack_lvl (lib/dump_stack.c:94 lib/dump_stack.c:120) [ 87.001599] print_report (mm/kasan/report.c:378 mm/kasan/report.c:482) [ 87.001599] kasan_report (mm/kasan/report.c:595) [ 87.001599] kasan_check_range (mm/kasan/generic.c:? mm/kasan/generic.c:200) [ 87.001599] rtrs_clt_stop_and_destroy_conns (./include/linux/instrumented.h:82 ./include/linux/atomic/atomic-instrumented.h:32 drivers/infiniband/ulp/rtrs/rtrs-clt.c:2237) [ 87.001599] rtrs_clt_close_work (drivers/infiniband/ulp/rtrs/rtrs-clt.c:2364) [ 87.001599] process_scheduled_works (kernel/workqueue.c:3396 kernel/workqueue.c:3479) [ 87.001599] worker_thread (kernel/workqueue.c:3560) [ 87.001599] kthread (kernel/kthread.c:436) [ 87.001599] ret_from_fork (arch/x86/kernel/process.c:158) [ 87.001599] ret_from_fork_asm (arch/x86/entry/entry_64.S:245) [ 87.001599] [ 87.001599] [ 87.001599] Allocated by task 1 on cpu 1 at 34.840929s: [ 87.001599] kasan_save_track (mm/kasan/common.c:57 mm/kasan/common.c:78) [ 87.001599] __kasan_kmalloc (mm/kasan/common.c:398 mm/kasan/common.c:415) [ 87.001599] alloc_path (./include/linux/slab.h:991 ./include/linux/slab.h:1312 drivers/infiniband/ulp/rtrs/rtrs-clt.c:1544) [ 87.001599] rtrs_clt_open (drivers/infiniband/ulp/rtrs/rtrs-clt.c:2870) [ 87.001599] rnbd_clt_map_device (drivers/block/rnbd/rnbd-clt.c:1268 drivers/block/rnbd/rnbd-clt.c:1551) [ 87.001599] rnbd_clt_map_device_store (drivers/block/rnbd/rnbd-clt-sysfs.c:612) [ 87.001599] kernfs_fop_write_iter (fs/kernfs/file.c:345) [ 87.001599] vfs_write (fs/read_write.c:595 fs/read_write.c:687) [ 87.001599] ksys_write (fs/read_write.c:739) [ 87.001599] do_syscall_64 (arch/x86/entry/syscall_64.c:61 arch/x86/entry/syscall_64.c:84) [ 87.001599] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121) [ 87.001599] [ 87.001599] Freed by task 1 on cpu 1 at 56.591404s: [ 87.001599] kasan_save_track (mm/kasan/common.c:57 mm/kasan/common.c:78) [ 87.001599] kasan_save_free_info (mm/kasan/generic.c:584) [ 87.001599] __kasan_slab_free (mm/kasan/common.c:253 mm/kasan/common.c:285) [ 87.001599] kfree (./include/linux/kasan.h:235 mm/slub.c:2748 mm/slub.c:6508 mm/slub.c:6801) [ 87.001599] kobject_put (lib/kobject.c:689 lib/kobject.c:720 ./include/linux/kref.h:65 lib/kobject.c:737) [ 87.001599] rtrs_clt_close (drivers/infiniband/ulp/rtrs/rtrs-clt.c:2933) [ 87.001599] free_sess (drivers/block/rnbd/rnbd-clt.c:754 drivers/block/rnbd/rnbd-clt.c:766) [ 87.001599] rnbd_clt_put_dev (drivers/block/rnbd/rnbd-clt.c:48 drivers/block/rnbd/rnbd-clt.c:61) [ 87.001599] rnbd_clt_unmap_device (drivers/block/rnbd/rnbd-clt.c:1703) [ 87.001599] rnbd_clt_unmap_dev_store (drivers/block/rnbd/rnbd-clt-sysfs.c:334) [ 87.001599] kernfs_fop_write_iter (fs/kernfs/file.c:345) [ 87.001599] vfs_write (fs/read_write.c:595 fs/read_write.c:687) [ 87.001599] ksys_write (fs/read_write.c:739) [ 87.001599] [ 87.001599] Last potentially related work creation: [ 87.001599] kasan_save_stack (mm/kasan/common.c:57) [ 87.001599] kasan_record_aux_stack (mm/kasan/generic.c:556) [ 87.001599] insert_work (kernel/workqueue.c:2272) [ 87.001599] __queue_work (kernel/workqueue.c:2448) [ 87.001599] queue_work_on (kernel/workqueue.c:2501) [ 87.001599] rtrs_clt_close_conns (./include/linux/workqueue.h:700 drivers/infiniband/ulp/rtrs/rtrs-clt.c:1967) [ 87.001599] rtrs_clt_rdma_cm_handler (drivers/infiniband/ulp/rtrs/rtrs-clt.c:2063) [ 87.001599] cma_cm_event_handler (drivers/infiniband/core/cma.c:2181) [ 87.001599] cma_process_remove (drivers/infiniband/core/cma.c:5313 drivers/infiniband/core/cma.c:5346) [ 87.001599] cma_remove_one (drivers/infiniband/core/cma.c:5453) [ 87.001599] remove_client_context (drivers/infiniband/core/device.c:810) [ 87.001599] disable_device (drivers/infiniband/core/device.c:1325) [ 87.001599] __ib_unregister_device (drivers/infiniband/core/device.c:1571) [ 87.001599] ib_unregister_device_and_put (drivers/infiniband/core/device.c:1636) [ 87.001599] nldev_dellink (drivers/infiniband/core/nldev.c:1902) [ 87.001599] rdma_nl_rcv (drivers/infiniband/core/netlink.c:? drivers/infiniband/core/netlink.c:239 drivers/infiniband/core/netlink.c:259) [ 87.001599] netlink_unicast (net/netlink/af_netlink.c:1338 net/netlink/af_netlink.c:1364) [ 87.001599] netlink_sendmsg (net/netlink/af_netlink.c:1919) [ 87.001599] __sock_sendmsg (net/socket.c:800 net/socket.c:815) [ 87.001599] __sys_sendto (net/socket.c:2281) [ 87.001599] __x64_sys_sendto (net/socket.c:2288 net/socket.c:2284 net/socket.c:2284) [ 87.001599] do_syscall_64 (arch/x86/entry/syscall_64.c:61 arch/x86/entry/syscall_64.c:84) [ 87.001599] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121) [ 87.001599] [ 87.001599] The buggy address belongs to the object at ffff888103867000 [ 87.001599] which belongs to the cache kmalloc-2k of size 2048 [ 87.001599] The buggy address is located 764 bytes inside of [ 87.001599] freed 2048-byte region [ffff888103867000, ffff888103867800) [ 87.001599] ================================================================== Best, Shuangpeng